Administering a Cluster

Creating the kubectl config

kubectl is the command line client used to control a kubernetes cluster. Kubernetes uses a separate authentication mechanism from OpenStack (Keystone). Since OpenStack already knows who we are, we can use it to generate a kubectl config file that includes credentials to authenticate us to Kubernetes.

1. Create a new directory and cd to it;

   mkdir mycluster
   cd mycluster
   

2. Use the openstack tool to generate the config file for kubectl:

   openstack coe cluster config mycluster
   export KUBECONFIG=/home/jake/temp/coe/mycluster/config
   

3. Set the KUBECONFIG environment variable used by copy-and-pasting the export KUBECONFIG=... line output by the above to the shell prompt:

   export KUBECONFIG=/home/jake/temp/coe/mycluster/config
   echo $KUBECONFIG
   /home/jake/temp/coe/mycluster/config
   

Using kubectl

1. Use kubectl to see if all your service pods in kubernetes are set up correctly. All the pods in the kube-system namespace should have status Running. For example:

   kubectl get all --all-namespaces
   

   NAMESPACE                NAME                                                                 READY   STATUS      RESTARTS       AGE
   calico-apiserver         pod/calico-apiserver-79dbf75bfc-997sh                                1/1     Running     0              45d
   calico-apiserver         pod/calico-apiserver-79dbf75bfc-wjqsz                                1/1     Running     0              45d
   calico-system            pod/calico-kube-controllers-5c7ffcfbf9-q75rz                         1/1     Running     0              45d
   calico-system            pod/calico-node-49dsv                                                1/1     Running     2 (45d ago)    45d
   calico-system            pod/calico-node-q69tj                                                1/1     Running     0              45d
   calico-system            pod/calico-typha-6c874f96b5-7w7pv                                    1/1     Running     0              45d
   calico-system            pod/csi-node-driver-hl9jm                                            2/2     Running     0              45d
   calico-system            pod/csi-node-driver-jqwrv                                            2/2     Running     0              45d
   kube-system              pod/coredns-7c65d6cfc9-fzqmp                                         1/1     Running     0              45d
   kube-system              pod/coredns-7c65d6cfc9-n7l9p                                         1/1     Running     0              45d
   [output truncated]
   

Using the web interface

Magnum used to ship its own Web UI Dashboard, with Magnum installing it by default. This is now deprecated and no-longer maintained, headlamp is now the recommended application for this.

Headlamp gives you a browser-based view of your cluster’s pods, deployments, services, logs and more.

Installation instructions can be found on the Headlamp site.